Flow-based and sieving matrix-free DNA differentiation by a miniaturized field flow fractionation device

DNA separation is typically done by gel electrophoresis based on its charge property. In our previous work, we reported that dielectrophoresis could be used to manipulate polystyrene nanoparticles' motion by using a miniaturized electrical field flow fractionation device (micro-EFFF) with a segmented electrode operated under a pulsed voltage (PV). In this work, we report the manipulation and separation of DNA molecules using the micro-EFFF. DNA motion was in situ visualized inside the device. Results revealed that dielectrophoresis governed DNA motion, which was strongly correlated with the pulse frequency but not the duty cycle of a PV. A longer retention time of DNA molecules was measured under a PV. The retention time increased with the length of DNA molecules. As the micro-EFFF is flow-based and sieving-matrix-free, it has a potential to be applied to sample preparation in a micrototal analysis system or when fractionated molecules are needed for downstream analysis.